title: Adverse drug reactions in Germany: direct costs of internal medicine hospitalizations.
abstract: OBJECTIVE
  German hospital reimbursement modalities changed as a result of the introduction of Diagnosis Related Groups (DRG) in 2004. Therefore, no data on the direct costs of adverse drug reactions (ADRs) resulting in admissions to departments of internal medicine are available. The objective was to quantify the ADR-related economic burden (direct costs) of hospitalizations in internal medicine wards in Germany.
  
  
  METHODS
  Record-based study analyzing the patient records of about 57,000 hospitalizations between 2006 and 2007 of the Net of Regional Pharmacovigilance Centers (Germany). All ADRs were evaluated by a team of experts in pharmacovigilance for severity, causality, and preventability. The calculation of accurate person-related costs for ADRs relied on the German DRG system (G-DRG 2009). Descriptive and bootstrap statistical methods were applied for data analysis.
  
  
  RESULTS
  The incidence of hospitalization due to at least 'possible' serious outpatient ADRs was estimated to be approximately 3.25%. Mean age of the 1834 patients was 71.0 years (SD 14.7). Most frequent ADRs were gastrointestinal hemorrhage (n = 336) and drug-induced hypoglycemia (n = 270). Average inpatient length-of-stay was 9.3 days (SD 7.1). Average treatment costs of a single ADR were estimated to be approximately €2250. The total costs sum to €434 million per year for Germany. Considering the proportion of preventable cases (20.1%), this equals a saving potential of €87 million per year.
  
  
  CONCLUSIONS
  Preventing ADRs is advisable in order to realize significant nationwide savings potential. Our cost estimates provide a reliable benchmark as they were calculated based on an intensified ADR surveillance and an accurate person-related cost application.
authors.affiliation: Ludwig-Maximilians-Universität München, Institute of Health Economics and Health Care Management and Munich Center of Health Sciences, Munich, Germany. rottenkolber@bwl.lmu.de
authors.forename: Dominik
authors.initials: D
authors.lastname: Rottenkolber
authors.forename: Sven
authors.initials: S
authors.lastname: Schmiedl
authors.forename: Marietta
authors.initials: M
authors.lastname: Rottenkolber
authors.forename: Katrin
authors.initials: K
authors.lastname: Farker
authors.forename: Karen
authors.initials: K
authors.lastname: Saljé
authors.forename: Silke
authors.initials: S
authors.lastname: Mueller
authors.forename: Marion
authors.initials: M
authors.lastname: Hippius
authors.forename: Petra A
authors.initials: PA
authors.lastname: Thuermann
authors.forename: Joerg
authors.initials: J
authors.lastname: Hasford
mesh_terms: D000293:Adolescent; D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D003365:Costs and Cost Analysis; D003627:Data Interpretation, Statistical; D064420:Drug-Related Side Effects and Adverse Reactions / Q000191:economics*; D005260:Female; D005858:Germany; D006748:Hospital Departments / Q000191:economics; D006760:Hospitalization / Q000191:economics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D055815:Young Adult